# host/utils - Host utilities. {{{ # # Copyright (C) 2009 Alexandre Stanislawski # # APBTeam: # Web: http://apbteam.org/ # Email: team AT apbteam DOT org # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # # }}} """Observable/Observer pattern.""" class Observable: """Derive from this object to be observable. An observable object will notify each of its observers every time it changes state.""" def __init__ (self): self.__observers = [ ] def register (self, observer): """Register an observer to this observable.""" assert callable (observer) self.__observers.append (observer) observer () def notify (self): """Notify all observers. This should be called after every state change.""" for observer in self.__observers: observer ()